One of the seven Endless, inconceivably powerful beings older and greater than gods, Dream is both lord and personification of all dream and stories, all that is not in reality (which, in turn, Dream may define by his existence). He has taken many names, including Morpheus and Oneiros, and his appearance can change depending on the person who is seeing him. Dream was named the sixth greatest comic book character by Empire Magazine.

Morpheus usually appears as a tall, thin man with bone-white skin, black hair, and two distant stars looking out from the shadows where his eyes should be. Most often they are silver or white, but when he becomes angered, they have been known to turn red.

Morpheus' appearance ranges widely 'depending on who's watching'. People generally perceive him as wearing a style of dress appropriate to their region and era. He appears to be light skinned when interacting with white characters, but the people of Tales in the Sand's primordial African city see him as a star-eyed black man. Although he is most often seen in human form, Morpheus appears as a huge black cat when speaking to the lonely cat-pilgrim of Dream of a Thousand Cats and as a cat-headed god when addressing the Egyptian feline goddess Bast. The Martian Manhunter sees Morpheus as a Martian god in the shape of a flaming alien skull and identifies him as Lord L'Zoril, but Mister Miracle, looking at him simultaneously, sees Morpheus as a man. However in Season of Mists, he appears in the same form to all the Gods (Bast comments "I much prefer you in cat form, Dream old friend"). In The Dream Hunters, which is set in ancient Japan, Morpheus appears as a Japanese man to a Buddhist monk and as a fox to a fox spirit. It is unclear whether Morpheus' appearance is determined by the expectations of onlookers or if he chooses to manifest himself in different forms. He does deliberately change the style of his clothing to be less conspicuous when he visits the waking world.